[MinnowBoard] Use SPI pins as GPIOs then switch them back to SPI mode problem

[Abdelghani Ouchabane]

Hi,

--------------------------------------------------------------------

   I need to talk to a CPLD, for that I need to use:

05      SPI_CS: SPI
07     SPIMISO: SPI
09     SPIMOSI: SPI
11     SPI_CLK: SPI

as GPIOs firstly then after the CPLD is ready, I want to use the above pins
as SPI interface to communicate with CPLD.

When I configure these pins as GPIOs, I see:

[   92.907050] byt_gpio INT33FC:00: pin 67 forcibly re-configured as GPIO
[   92.907524] byt_gpio INT33FC:00: pin 68 forcibly re-configured as GPIO
[   92.908612] byt_gpio INT33FC:00: pin 66 forcibly re-configured as GPIO
[   92.909134] byt_gpio INT33FC:00: pin 69 forcibly re-configured as GPIO
[   92.917893] byt_gpio INT33FC:00: pin 94 forcibly re-configured as GPIO

But when I switch them to SPI back, these pins still are GPIOs.

"    // Configure SPI
     if ( !(m_spi = mraa_spi_init(this->m_bus)) )
     {
         throw std::invalid_argument(std::string(__FUNCTION__) +
                                         ": mraa_spi_init() failed");
         return;
     }

     configSPI();
"

Any help please on how to switch between GPIO and SPI mode without
rebooting?

--------------------------------------------------------------------
Brendan Le Foll:

Sadly with the current pinctrl driver on baytrail there is no way.

Cheers,
Brendan
--------------------------------------------------------------------

As I understood it is a hardware limitation. So there is no way to get
it works by updating the Linux kernel?

Do you know if the new MinnowBoard Turbo Quad supports that functionality?

Thanks
Ghani


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